Subgraph boundaries — Conway's Law is the API
Where you cut your subgraphs determines whether federation liberates your teams or gives them a distributed monolith. The cut is organisational first, technical second.
Schema governance & CI — composition as a contract
A federated graph is a distributed system whose type system spans repositories. Governance is what keeps 30 teams from breaking each other — and it must be automated, because policy documents don't block merges.
Operating the router — the new tier-0 service
The day you adopt federation, your router becomes the single most critical service you run: 100% of API traffic, every page, every client. Operate it like it.
The client experience — one graph, no seams
Federation's promise to clients is that the supergraph looks like one coherent API. Keeping that promise is a set of deliberate practices — break them and clients start routing around your graph.